The present invention relates to a motor-driven fluid machine having an electric motor that rotates a rotary shaft and a drive circuit that drives the electric motor.
Japanese Laid-Open Patent Publication No. 2014-34918, for example, discloses a motor-driven compressor including a compressing portion, which is driven through rotation of a rotary shaft to compress refrigerant. The housing of the motor-driven compressor accommodates the compressing portion and an electric motor. The electric motor includes a stator, which is fixed to an inner peripheral surface of the housing, and a rotor, which is rotated integrally with the rotary shaft. The stator has a cylindrical stator core and a U-phase coil, a V-phase coil, and a W-phase coil, which are wound around the stator core. An annular coil end projects from an end face of the stator core at an end with respect to the axial direction of the rotary shaft. Three motor wires corresponding to the U-phase, V-phase, and W-phase coils are routed out of the coil end. A drive circuit has circuit wires, each of which is electrically connected to the corresponding one of the motor wires.
The housing accommodates an insulating cluster block, which accommodates conductive members that establish electrical connection between the motor wires and the circuit wires. Each of the motor wires is electrically connected to the corresponding one of the conductive members. The motor wires are thus electrically connected to the corresponding circuit wires through the corresponding conductive members. The drive circuit is thus allowed to supply electric power to the electric motor through the circuit wires, the conductive members, and the motor wires, thus driving the electric motor. This rotates the rotary shaft to drive the compressing portion, thus compressing refrigerant by means of the compressing portion.
As illustrated in FIG. 4, to avoid interference between three motor wires 101 and components located inside a stator core 102 (such as a rotary shaft 104 and a bearing portion), the motor wires 101 may each be routed to extend in a circumferential direction of the rotary shaft 104 on an outer end portion 103e of a coil end 103, which is located at an end with respect to the axial direction of the rotary shaft 104. The motor wires 101 face the same direction while extending in the circumferential direction of the rotary shaft 104 from the coil end 103. To minimize the projecting dimension of the motor wires 101 outward in the axial direction of the rotary shaft 104 from the outer end portion 103e of the coil end 103, parts of the motor wires 101 are located adjacently in the radial direction of the rotary shaft 104 in some cases.
To reduce the size of the motor-driven compressor in the radial direction and the axial direction of the rotary shaft 104, a cluster block 106 is arranged on the stator core 102, at times, the three conductive members 105 are located inward in the radial direction of the rotary shaft 104 with respect to the coil end 103.
It is now assumed that, in the sections of the motor wires 101 located adjacently in the radial direction of the rotary shaft 104, the innermost one of the motor wires 101 in the radial direction of the rotary shaft 104 extends in the circumferential direction of the rotary shaft 104 while being maintained in a state facing a section of the outer end portion 103e of the coil end 103 that is located inward in the radial direction of the rotary shaft 104. In this configuration, when connecting the motor wire 101 to the corresponding conductive member 105, an end of the motor wire 101 corresponding to the conductive member 105 is bent at an acute angle toward the conductive member 105 in some cases. This is likely to increase the load (stress) on the motor wire 101.